http://www.translink.ca/en/Fares-and-Passes/Fare-Infractions/FAQs.aspx
What happens if I don't pay my fare infraction ticket?
If you don't pay your fare infraction ticket, it may be sent to a collection agency and/or you may not be able to get or renew your driver's licence and/or get or renew your vehicle insurance. 180 days after the fare infraction ticket was issued (except as set out in the fare collection bylaw), the ticketed amount will go up by $40 (to $213). 366 days after the ticket was issued, it will go up by $60 more (to $273).
と書かれてますが、実際のところ払わない外国人旅行者は多いと思われます。
今後カナダに戻ってくる予定が一切無いなら平気でしょうけど、将来カナダに住む予定なら記録に残ってるかもしれません。
そうすると上に書いてあるように、運転免許取れなかったり車に保険かけられなかったり、ということになります。